[webui] Integrate generate_code_cache into build_webui

This CL integrates the generate_code_cache() webui build rule into
build_webui to simplify integration of existing webui resources.

The generate_code_cache optimize param is introduced to build_webui
and will enable the generate_code_cache step provided optimize and
minify configurations are specified. Further this will only apply
in cases where the enable_webui_generate_code_cache webui_feature
is true.

If enabled and configured correctly a grdp rule is introduced by
the build_webui template that can be used to aggregate the code
cache resources into a single grd for integration into the
resource bundle.

This CL also demonstrates use of the build rule by integrating
cr_elements into the //ui/webui/resources:code_cache_resources
target.

Bug: 378504039
Change-Id: Iab1a044201d45ac93d66478dbff39d0195894948
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6332418
Reviewed-by: Demetrios Papadopoulos <dpapad@chromium.org>
Commit-Queue: Tom Lukaszewicz <tluk@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1430546}

docs/webui/webui_build_configuration.md

@@ -594,9 +594,10 @@ Under the cover, build_webui() defines the following targets
 10. `merge_js_source_maps("merge_source_maps")`
 11. `bundle_js("build_bundle")`
 12. `minify_js("build_min_js")`
-13. `generate_grd("build_grd")`
-14. `generate_grd("build_grdp")`
-15. `grit("resources")`
+13. `generate_code_cache("build_code_cache")`
+14. `generate_grd("build_grd")`
+15. `generate_grd("build_grdp")`
+16. `grit("resources")`
 
 Some targets are only conditionally defined based on `build_webui()` input
 parameters.
@@ -681,6 +682,10 @@ optimize_webui_excludes: See |excludes| in bundle_js(). Optional.
 optimize_webui_external_paths: See |external_paths| in optimize_webui().
                                Optional.
 optimize_webui_in_files: See |in_files| in bundle_js().
+generate_code_cache: Specifies whether code cache resources should be generated
+                     for the minified files. Use
+                     `generate_code_cache = enable_webui_generate_code_cache` to
+                     opt-in.
 
 Other params:
 webui_context_type: See |webui_context_type| in webui_path_mappings(). Optional,

tools/gritsettings/resource_ids.spec

@@ -1447,7 +1447,7 @@
     "includes": [9980],
   },
   "<(SHARED_INTERMEDIATE_DIR)/ui/webui/resources/webui_code_cache_resources.grd": {
-    "META": {"sizes": {"includes": [10]}},
+    "META": {"sizes": {"includes": [200]}},
     "includes": [9990],
   },
   "<(SHARED_INTERMEDIATE_DIR)/ui/webui/resources/webui_resources.grd": {

ui/webui/resources/BUILD.gn

@@ -174,10 +174,15 @@ if (enable_webui_generate_code_cache) {
   generate_grd("build_code_cache_grd") {
     grd_prefix = "webui_code_cache"
     out_grd = "$target_gen_dir/${grd_prefix}_resources.grd"
-    grdp_files =
-        [ "$root_gen_dir/third_party/lit/v3_0/code_cache_resources.grdp" ]
+    grdp_files = [
+      "$root_gen_dir/third_party/lit/v3_0/code_cache_resources.grdp",
+      "$target_gen_dir/cr_elements/code_cache_resources.grdp",
+    ]
 
-    public_deps = [ "//third_party/lit/v3_0:build_code_cache_grdp" ]
+    public_deps = [
+      "cr_elements:build_code_cache_grdp",
+      "//third_party/lit/v3_0:build_code_cache_grdp",
+    ]
   }
 
   grit("code_cache_resources") {

ui/webui/resources/cr_elements/BUILD.gn

@@ -3,6 +3,7 @@
 # found in the LICENSE file.
 
 import("//ui/webui/resources/tools/build_webui.gni")
+import("//ui/webui/webui_features.gni")
 
 build_webui("build") {
   grd_prefix = "webui_cr_elements"
@@ -251,4 +252,5 @@ build_webui("build") {
   webui_context_type = "relative"
   generate_grdp = true
   grd_resource_path_prefix = rebase_path(".", "//ui/webui/resources")
+  generate_code_cache = enable_webui_generate_code_cache
 }

ui/webui/resources/tools/build_webui.gni

@@ -16,6 +16,7 @@ import("//tools/typescript/webui_path_mappings.gni")
 import("//ui/webui/resources/tools/bundle_js.gni")
 import("//ui/webui/resources/tools/bundle_js_excludes.gni")
 import("//ui/webui/resources/tools/eslint_ts.gni")
+import("//ui/webui/resources/tools/generate_code_cache.gni")
 import("//ui/webui/resources/tools/generate_grd.gni")
 import("//ui/webui/resources/tools/minify_js.gni")
 import("//ui/webui/webui_features.gni")
@@ -80,6 +81,11 @@ template("build_webui") {
     generate_grd_target_name = "build_grdp"
   }
 
+  generate_code_cache = false
+  if (defined(invoker.generate_code_cache)) {
+    generate_code_cache = invoker.generate_code_cache
+  }
+
   ### Compute the lists of files that are used across multiple targets.
 
   # At least one of `web_component_files`, `css_files`, `mojo_files`, or
@@ -507,7 +513,10 @@ template("build_webui") {
 
   if (minify) {
     minify_js("build_min_js") {
-      visibility = [ ":$generate_grd_target_name" ]
+      visibility = [
+        ":$generate_grd_target_name",
+        ":build_code_cache",
+      ]
       in_folder = ts_out_dir
       in_target = ":build_ts"
       if (bundle) {
@@ -526,6 +535,36 @@ template("build_webui") {
     }
   }
 
+  if (generate_code_cache) {
+    generate_code_cache("build_code_cache") {
+      visibility = [ ":build_code_cache_grdp" ]
+
+      # Rebase the minified file paths under the minified directory.
+      minified_outputs =
+          filter_include(get_target_outputs(":build_min_js"), [ "*.js" ])
+      in_files = []
+      foreach(minified_output, minified_outputs) {
+        in_files += [ rebase_path(minified_output, "$target_gen_dir/minified") ]
+      }
+
+      in_folder = "$target_gen_dir/minified"
+      out_folder = "$target_gen_dir/code_cache"
+      out_manifest = "$target_gen_dir/build_code_cache_manifest.json"
+
+      deps = [ ":build_min_js" ]
+    }
+
+    generate_grd("build_code_cache_grdp") {
+      if (defined(invoker.grd_resource_path_prefix)) {
+        resource_path_prefix = invoker.grd_resource_path_prefix
+      }
+      grd_prefix = grd_prefix + "_code_cache"
+      out_grd = "$target_gen_dir/code_cache_resources.grdp"
+      manifest_files = [ "$target_gen_dir/build_code_cache_manifest.json" ]
+      deps = [ ":build_code_cache" ]
+    }
+  }
+
   generate_grd(generate_grd_target_name) {
     if (!generate_grdp) {
       visibility = [ ":resources_grit" ]

ui/webui/resources/tools/generate_code_cache.gni

@@ -9,6 +9,7 @@ template("generate_code_cache") {
     forward_variables_from(invoker,
                            [
                              "deps",
+                             "visibility",
                              "in_folder",
                              "in_files",
                              "out_folder",

ui/webui/webui_features.gni

@@ -27,14 +27,22 @@ declare_args() {
   # and build) with the runtime --load-webui-from-disk command line switch.
   load_webui_from_disk = false
 
-  # Enable generation of compiled JS bytecode for opted-in WebUI scripts. When
-  # the host and current toolchains are the same there are issues instrumenting
-  # the code_cache_generator msan binaries, see crbug.com/40055221#comment17.
-  # TODO(crbug.com/399764218): Enable this build-step on cross-compiled builds.
-  # This is necessary for universalized mac builds that produce x64 / arm64
-  # chrome builds in the same package.
+  # Enable generation of compiled JS bytecode for opted-in WebUI scripts for
+  # compatible build configurations (see comment for the
+  # `enable_webui_generate_code_cache` update below).
+  enable_webui_generate_code_cache = false
+}
+
+# Build-time WebUI code caching is only used in optimize_webui builds. When the
+# host and current toolchains are the same there are issues instrumenting the
+# code_cache_generator msan binaries, see crbug.com/40055221#comment17.
+# TODO(crbug.com/399764218): Enable this build-step on cross-compiled builds.
+# This is necessary for universalized mac builds that produce x64 / arm64 chrome
+# builds in the same package.
+if (enable_webui_generate_code_cache) {
   enable_webui_generate_code_cache =
-      host_toolchain == current_toolchain && !is_msan && (is_linux || is_win)
+      optimize_webui && host_toolchain == current_toolchain && !is_msan &&
+      (is_linux || is_win)
 }
 
 if (load_webui_from_disk) {